1. Field of the Invention
This invention relates to vapor cycle air conditioning and heat pump systems. More particularly, this invention relates to systems designed to recover refrigerant within an air conditioning or heat pump system and purify the same for later re-use in the same or other air conditioning or heat pump systems.
2. Description of the Background Art
During the operation of any air conditioning and heat pump system, the refrigerant will become increasingly contaminated by particulate and liquid matter. Eventually, the refrigerant will suffer a degradation of its thermodynamic properties from being contaminated. Hence, refrigerant is typically bled from the system to the atmosphere. After bleeding, the refrigerant system is flushed with an inexpensive gas, such as that sold under the trademark Freon 11, to remove the contaminants and oil which may still exist in the system after bleeding. After bleeding and flushing, the refrigerant system is recharged with new refrigerant. Since the oil in the refrigerant was also bled from the system, the system must also be refilled with a proper amount of oil to be again mixed with the refrigerant for circulation throughout the system.
In addition to general maintenance procedures on refrigerant systems, it is also necessary to bleed the refrigerant to the atmosphere whenever the closed circuit of the refrigerant system is repaired. Indeed, the repair of many components of the refrigerant system (such as the compressor, evaporator, condenser and throttling device) typically require that the entire system be bled of the refrigerant and then, after the repair, recharged.
Obviously, the wasteful bleeding of the refrigerant to the atmosphere is undesirable, both economically and environmentally, inasmuch as some refrigerants (such as Freon) are believed to adversely affect the ozone layer of the earth's atmosphere. Indeed, several refrigerant recovery systems have been developed in various attempts to efficiently recover the refrigerant from the refrigerant system for storage and subsequent recharging of the refrigerant system. The refrigerant recovery systems presently known include those described in U.S. Pat. Nos. 3,232,070, 4,261,178, 4,285,206, 4,363,222 and 4,476,688, the disclosures of which are hereby incorporated by reference herein.
The earliest patent listed above discloses the simplest form of a refrigerant recovery system as including a compressor having its suction inlet connected to the refrigerant system to be evacuated. A condenser is connected to the outlet of the compressor to condense the evacuated refrigerant. The condensed, liquified refrigerant flows through a dryer/strainer into a storage tank. U.S. Pat. No. 4,261,178 and its divisional (4,363,222) discloses a refrigerant recovery system utilizing a positive displacement transfer pump to evacuate the refrigerant from the refrigerant system and flow the evacuated refrigerant through a condenser and then storing the liquid refrigerant in a tank. U.S. Pat. No. 4,285,206 discloses a microprocessor-controlled refrigerant recovery system. Finally, U.S. Pat. No. 4,476,688 discloses a refrigerant recovery system in which refrigerant from the refrigerant system is drawn through an oil trap and acid purification filter/dryer by means of a compressor and then into a condenser. The liquid refrigerant then flows through another acid purification filter/dryer for storage in a receiving tank. A portion of the liquid refrigerant from the receiving tank flows through a return line into a heat exchanger adapted to assist in the condensing of the gaseous refrigerant in the condenser and then recirculate it to the suction side of the compressor.
A major disadvantage to the systems described above is their inability to completely purify the refrigerant during the evacuation and recovery process. Indeed, conventional oil traps and filters only provide a certain degree of purification which, of course, gradually degrades during use until the oil traps and filters are only marginally effective in removing impurities. Consequently, during recharging, the impurities and other contaminants still contained in the refrigerant is undesirably placed back into the refrigerant system even though the refrigerant system may have been properly and effectively flushed of all contaminants.
A still further disadvantage to the systems noted above (based at least in part upon actual use in regard to the unit manufactured and sold by the owner of U.S. Pat. No. 4,476,688) is that the recovery systems do not completely or quickly evacuate the refrigerant from the refrigerant system. Experience has shown that adequate evacuation of the refrigerant can only be attained during operation of the recovery unit over a significantly prolonged period of time. Consequently, the evacuation time required to adequately recover the refrigerant significantly precludes commercial use of the recovery units in applications where speed is important.
Therefore, it is an object of this invention to provide an apparatus and method which overcomes the aforementioned inadequacies of the prior art and provides an improvement which is a significant contribution to the advancement of the refrigerant recovery and purification art.
Another object of this invention is to provide a refrigerant recovery purification system operable to quickly and substantially completely evacuate refrigerant from a refrigerant system for storage in a tank for later re-use.
Another object of this invention is to provide a refrigerant recovery and purification system operable to recover refrigerant from a refrigerant system and purify the same for later storage and re-use.
Another object of this invention is to provide a refrigerant recovery and purification system in which the refrigerant evacuated from the refrigerant system is purified during the recovery process by evaporating the evacuated refrigerant in a tank to distill the evaporated refrigerant from the oil and contaminants thereby purifying the refrigerant to almost its absolute form.
Another object of this invention is to provide a refrigerant recovery and purification system in which the recovered refrigerant is purified by means of an evaporation/distillation process and in which a closed-loop oil separator is fluidly connected to the compressor to circulate oil therethrough, thereby precluding premature burn-out of the compressor which would otherwise occur from compressing refrigerant containing no oil.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.